Components and working principles of an internal combustion engine driven generator will be introduced first below.
Referring to FIG. 1, the figure is a structural diagram of an internal combustion engine driven generator in the prior art.
An internal combustion engine driven generator 101, functioning as a prime motor, drives a generator 102 to generate electricity. An alternating current outputted by the generator 102 is rectified into a direct current by a rectifying unit 103, and the direct current is outputted to an inverter unit 104 subsequently. Controlled by a controller 105, the inverter unit 104 inverts the direct current into a required alternating current which is provided to a load after being filtered by a filter unit 106. At the same time, the controller 105 controls the opening degree of the throttle of the internal combustion engine 101 through a throttle controller 107.
The generator needs to provide relatively large power output in some application scenarios. However, the requirement may not be satisfied by one generator. For example, the output power of one generator is 1.6 kW, but a power of 3 kW is required by a load. In this way, two generators connected in parallel are needed to provide power for the load.
As shown in FIG. 2, the figure is a schematic diagram illustrating a plurality of generators connected in parallel to provide power for a load in the prior art.
The parallel system includes two generators, each of which corresponds to an internal combustion engine. The output ends of the generators are connected in parallel to provide power for the load.
Since power supply to a load by two generators connected in parallel and a photovoltaic inversion connected grid are two power supply methods which are completely different. The photovoltaic inversion connected grid only needs the same phase and frequency as those of a power grid and does not need to realize power balance among generators connected in parallel during photovoltaic inversion. However, power balance needs to be realized among generators to supply power to a load by generators connected in parallel.
Therefore, how to control internal combustion engine driven generators to run in parallel is a problem to be solved by those skilled in the art.